Detergent tablets



United States Patent Ofifice 3,043,779 Patented July 10,. 1962 3,043,779 DETERGENT TABLETS John Pedlow Parke, Bebington, and David Dutton Penketh, Bromborough, England, assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Filed Mar. 13, 1958, Ser. No. 721,110 Claims priority, application Great Britain Mar. 18, 1957 9 Claims. (Cl. 252-117) This invention relates to detergent compositions in tablet, i.e. bar or cake, form, and has special reference to reducing their tendency to become soft and sticky during use.

Detergent tablets for toilet use, besides having an effective lathering and detergent action, should be hard and coherent, should not become soft, slimy or sticky in use or on storage after use and should not dissolve too rapidly in warm water. All these properties are possessed to a useful degree by soap tablets which, however, have the grave disadvantage that they give a scum of calcium and magnesium soaps in hard water which is unpleasant to the fel,-is difiicult to remove from the skin completely,

so that the cleansing action of the soapis partly nullified,

and leaves unsightly marks on the sides of wash-bowls and baths in which the tablets are used. It has frequently been proposed to incorporate in soap tablets substances which will so solubilize or disperse the calcium and magnesium soaps formed in hard water that the objectionable phenomena referred to above are eliminated. Such substances are normally synthetic soapless detergents. The addition of synthetic soapless detergents to soap, however, often gives tablets which have an undesirably high rate of solution and which tend to become soft and sticky in use and on storage after use.

It has now been found that these difficulties can be reduced or eliminated in the case of certain compositions containing soap and synthetic organic detergents in tablet form by incorporating in them certain water soluble organic salts.

The invention provides, therefore, a detergent composition in tablet form containing a major proportion of soap, a minor proportion of a water-soluble fattyacylaminomethane sulphonate and a small proportion of a water-soluble salt of an organic monocarboxylic or monosulphonic acid having from 1 to 8 carbon atoms in the molecule.

The soap to be used in the tablets of the invention may be any soap normally used in the manufacture of soap tablets, such as the sodium and potassium, soaps derived from palm kernel oil, coconut oil, fallow, and the like, and mixtures of them. It is preferred to use a mixture of approximately equal parts of sodium palmkernel-oil soap and sodium tallow soap.

The fatty-acyl-aminomethane sulphonates to be used in the compositions of the invention include the sodium and potassium salts of fatty acyl-arninomethane sulphonic acids having the general formula.

in which the fatty acyl radicals R.CO. have from about 8 to about 18 carbon atoms and may be saturated or unsaturated. Compounds having mixed acyl groups and derived from the fatty acids of natural oils and fats such as palm oil, palm kernel oil, coconut oil and tallow, which may be partially hardened, can be used with advantage. Preferred compounds are sodium palm-kernel-fatty-acylaminomethane sulphonate and sodium partly-hardenedtallow-fatty-acyl-methyl-aminomethane sulphonate.

The lower organic salts which are used in the tablets of the invention include: the sodium and potassium salts of the lower unsubstituted straight-chain aliphatic monocarboxylic acids such as sodium or potassium formate, acetate, propionate, butyrate, caproate and 'caprylate; of branched chain aliphatic monocarboxylic acids; of aromatic monocarboxylic acids such as sodium benzoate; of lower alkane sulphonic acids; of aromatic mono-sulphonic acids such as scdiurn toluene and Xylene sulphonates; and salts of mono-carboxylic acids and mono-sulphonic acids having substituents such as hydroxy and amino groups and halogen atoms as, for example, sodium lactate, sodium hydroxymethane sulphonate (sodium formaldehyde bisulphite), sodium beta-hydroxy-ethane sulphonate (so dium isethionate), and sodium methyltauride. Mixtures of these compounds may be used. It is preferred to use sodium formate or sodium lactate, the latter in particular giving soap tablets of very desirable characteristics.

Many preparations of fotty-acyl-aminomethane sulphonates already contain a minor proportion of sodium formaldehyde bisulphite or sodium aminomethane sulphonate present as impurities, but the amount of these salts present as impurities is too small to be of any benefit. Any added salt may be the same as or different from that already present as an impurity.

The tablets of the invention may contain from about 55% to of soap, from about 15% to 30% of fattyacyl-aminomethane sulphonate and from about 0.5% to 10%, generally preferably 1% to 3%, of lower carboxylate or sulphonate. The percentages are by weight, based on the weight of the entire tablet.

The compositions of the invention may also contain, as an optional scum-reducing aid, a proportion of one or more of the surfaceactive nonionic substantially nondetergent compounds of British Patent No. 750,495, namely: alkyl-phenols having from 3 to 10 carbon atoms in the alkyl group, and ethers of such phenols with polyhydric alcohols, such as p-n-butyl phenol and ptert.- octylphenyl alpha-glycerol ether; partial esters of polyhydric alcohols and C fatty acids, such as glyceryl mono-palmitate; saturated and unsaturated C1048 fatty alcohols, such as oleyl alcohol; and amides and alkanolamides of C1048 fatty acids, such as lauramide and palmitic mono-ethanolamide. It is preferred touse amides of C1048 fatty acids.

Many preparations of fatty-acyl-aminomethane sulphonates already contain aproportion of fatty amide and this may in some cases be sufficient for the required com positions. Any of the above scum-reducing aids may be used in conjunction with preparations already containing some fatty amide, and where amide is added it may be the same as or different from that already present. Up to about 10% of such scum-reducing aid may be present in the tablets of the invention.

The tablets of the invention may also contain superfatting agents such as lanolin and stearin, and other free fatty acids, in conventional amounts. They may also contain any of the usual minor ingredients of soap tablets such as rosin, dyes, opacifiers, perfumes, stabilizers and the like. The compositions may contain small amounts of inorganic salts such as may be introduced as impurities with the main ingredients, but such impurities should be kept to a minimum since too high a proportion of inorganic salts leads to cracking and efllorescence of the tablets on storage.

The tablets of the invention may be made by mixing the soap in the form of dried chips with the fatty-acyl-aminomethane sulphonate and scum-reducing aid, if any, in powder or flake form, adding the lower organic salt as a fine powder or as a concentrated aqueous solution, and, after thorough milling, plodding and stamping the mixture by the methods normally used for soap tablets. It may be preferable in some cases, however, to form a homogeao-iawe phonate and 575% of its weight of water in a crutcher at 75-80 C., and then to add, with stirring, the soap in the form of a liquid soap base of 63% total-fatty matter content, the amide or other scum-reducing aid, also in liquid form, and finally the lower organic salt in the form of a fine powder or as a concentrated aqueous solution. After thorough mixing, the product may be dried, for instance in a tubular drier, cooled, milled and plodded.

The following examples are given solely for purposes of illustration and are not to be considered as limiting the invention to these embodiments. Many modifications will be apparent to those skilled in the art without departing from the spiritor scope of the invention.

EXAMPLES A base mixture of the following composition was made:

Tablets were formed under the same conditions from portions of this base mixture without additives and from other portions to which various amounts of organic salts as indicated in the tablebelow had been added. The tablets were tested by the following method.

Stainless steel rings, 2.54 cm. ininternal diameter and 1.9 cm. high, were pressed about 0.25 cm. into the upper surface of each of the tablets and 5 ml. of water were poured into 'each ring and the whole weighed. After standing 16 hours at room temperature (23 C.) the unabsorbed water was poured off, the inside surface of the rings dried with filter paper and the whole reweighed. The tablets'were then allowed to stand for 8 hours at 23 C., after which the rings were removed and the softness of the treated portions of the tablets was measured by means of a penetrometerunder standard conditions.

The results are given in the table below:

What is claimed, is;

1. A detergent composition in the form of ahard, co herent tablet which does not become soft and slimy or' sticky on being used or stored after use and which does not dissolve with undesirable rapidity in warm water, comprising from about 55% to about 85 of a water-soluble alkali metal soap, from about 15% to about 30% of a water-soluble alkali metal fatty-acyl-aminomethane sul-.

phonate wherein the fatty-acyl radical has from about 8 to about 18 carbon atoms, and from about 0.5% to about of a water-soluble salt of an organic acid selected from the group consisting of monocarboxylic and monosulphonic acids having from 1 to 8 carbon atoms in the molecule, the percentages being by weight based on the weight of the entire tablet.

2. A detergent composition in tablet form as in claim 1 which additionally contains up to about 10% of a surface active, nonionic, substantially non-detergent, scumreducing aid selected from the group consisting of alkylphenols having from 3 to 10 carbon atoms in the alkyl group, ethers of such phenols with polyhydric alcohols, partial esters of polyhydric alcohols and fatty acids containing from- 10 to 18 carbon atoms, saturated and unsaturated fatty alcohols containing from 10 .to 18 carbon atoms, and amides and alkanolamides of fatty acids containing from 10 to 18 carbon atoms.

3. A detergent composition in the form of a hard, coherent tablet which does not become soft and slimy or sticky on being used or stored after use and which does not dissolve with undesirable rapidity in warm water, comprising from about 55% to about 85% of a Water-soluble alkali metal soap, from about 15 to about 30% of a water-soluble alkali metal fatty-acyl-aminomethane sulphonate wherein the fatty acyl radical has from about 8 to about 18 carbon atoms, and from about 1% to about 3% of a water-soluble salt of an organic acid selected from the group consisting of monocarboxylic and monosulphonic acids having from 1 to 8 carbon atoms in the molecule, the percentages being by weight based on the weight of the entire tablet.

4. A detergent composition in tablet form as in claim 3 which additionally contains up to about 10% of a surface active, nonionic, substantially non-detergent, scum-reducing aid selected from the group consisting of alkyl-phenols having from 3 to 10 carbon atoms in the alkyl group, ethers of such phenols with polyhydric alcohols, partial esters of polyhydric alcohols and fatty acids containing from 10 to 18 carbon atoms, saturated and unsaturated fatty alcohols containing from 10 to 18 carbon atoms and amides and alkanolamides of fatty acids containing from 10 to 18 carbon atoms.

5. A detergent composition in the form of a hard, coherent tablet which does not become soft and slimy or sticky on being used or stored after use and which does not dissolve with undesirable rapidity in Warm water comprising from about 55 to about-85% of a Water-soluble alkali metal soap, from about 15 to about 30% of'a Water-soluble alkali metal fatty-acyl-aminomethane sulphonate wherein the fatty-acyl radical has from about 8 to about 18 carbon atoms, and from about 0.5 to about 10% of sodium lactate, the perecentages being by weight based on the weight of the entire tablet.

6. A detergent composition in tablet form as in claim 5 which additionally contains up to about 10% of a surface-active, nonionic, substantially non-detergent, scumreducing aid selected from the group consisting of alkylphenols having from 3 to 10 carbon atoms in the alkyl group, ethers of such phenols with polyhydric alcohols, partial estersv of polyhydric alcohols and fatty acids containing from 10 to 18' carbon atoms, saturated and unsaturated fatty alcohols containing from 10 to 18 carbon atoms, and amides and alkanolamides of fatty acids containing from 10 to 18 carbon atoms.

7. A detergent composition in the form of a hard, coherent tablet which does not become soft and slimy or sticky on being used or stored after use and which does not dissolve with undesirable rapidity in warm water comprising from about 55% to about 85% of a water-soluble alkali metal soap, from about 15% to about 30% of a water-soluble alkali metal fatty-acyl-aminomethane sulphonate wherein the fatty-acyl radical has from about 8 to about 18 carbon atoms and from about 0.5 to about 10% of sodium formate, the percentages being by weight based on the weight of the entire tablet.

8. A detergent composition in tablet form as in claim 7 which additionally contains up to about 10% of a surfaceactive, nonionic, substantially non-detergent, scum-reducing aid selected from the group consisting of alkyl-phenols having from 3 to 10 carbon atoms in the alkyl group, ethers of such phenols with polyhydric alcohols, partial esters of polyhydric alcohols and fatty acids containing from 10 to 18 carbon atoms, saturated and unsaturated fatty alcohols containing from 10 to 18 carbon atoms, and amides and alkanolamides of fatty acids containing from 10 to 18 car-hon atoms.

5 9. A detergent composition in the form of a hard, c0- herent tablet which does not become soft and slimy or sticky on being used or stored after use and which does not dissolve with undesirable rapidity in warm water comprising from about 55% to about 85% of a water-soluble alkali metal soap, from about 15% to about 30% of a water-soluble alkali metal fatty-acyl-aminomethane sulphonate wherein the fatty-aeyl radical has from about 8 to about 18 carbon atoms, and from about 0.5% to about 10% of a water-soluble salt of an organic acid selected and hydroxy monocarboxylic acids having from 1 to 8 carbon atoms in the molecule, the percentages being by weight based on the weight of the entire tablet.

References Cited in the file of this patent from the group consisting of aliphatic monocarboxylic 10 2,731,320

UNITED STATES PATENTS Liddle May 10, 1921 Preston Oct. 24, 1950 Henkin Apr. 6, 1954 Faier June 5, 1956 Jelinek et a1 Feb. 12, 1957 

1. A DETERGENT COMPOSITION IN THE FORM OF A HARD, COHERENT TABLET WHICH DOES NOT BECOME SOFT AND SLIMY OR STICKY ON BEING USED OR STORED AFTER USE AND WHICH DOES NOT DISSOLVE WITH UNDESIRABLE RAPIDITY IN WARM WATER, COMPRISING FROM ABOUT 55% TO ABOUT 85% OF A WATER-SOLUBLE ALKALI METAL SOAP, FROM ABOUT 15% TO ABOUT 30% OF A WATER-SOLUBLE ALKALI METAL FATTY-ACYL-AMINOMETHANE SULPHONATE WHEREIN THE FATTY-ACYL RADICAL HAS FROM ABOUT 8 TO ABOUT 18 CARBON ATOMS, AND FROM ABOUT 0.5% TO ABOUT 10% OF A WATER-SOLUBLE SALT OF AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF MONOCARBOXYLIC AND MONOSULPHONIC ACIDS HAVING FROM 1 TO 8 CARBON ATOMS IN THE MOLECULE, THE PERCENTAGES BEING BY WEIGHT BASED ON THE WEIGHT OF THE ENTIRE TABLET. 